In recent years, there has been a rapid and expansive growth of mobile phone use. In addition to a communication function, models currently available include those equipped with various functions such as sending and receiving electronic mails and camera functions. Call forwarding services which forward an incoming call to another telephone have been conventionally used. However, a mobile phone may frequently experience interruptions in communication since a mobile phone is carried by a user and is movable to various locations including those where signals are too weak to establish communication, or since the user may choose to switch off the mobile phone to avoid bothering other people. As a result, call forwarding services are becoming more and more important.
To use a call forwarding service, a user must operate his/her mobile phone and register a forwarding destination phone number in advance to a call forwarding service center. The mobile phone must also be operated every time a forwarding destination is changed. Many users may consider this to be burdensome. Accordingly, it is difficult for a user to perform operations in order to change forwarding destinations in response to moment-to-moment circumstances.
With respect to a call forwarding service, in order to enable forwarding even when forwarding is not set at a receiving-side phone or when the receiving-side phone is busy, Patent Document 1 proposes a method in which a wireless base station-side control apparatus manages positional information of respective mobile phones as well as groups to which the respective mobile phones belong, and in the event that a mobile phone is unable to receive an incoming call, the wireless base station-side control apparatus determines a mobile phone that is in the same wireless communication area as the mobile phone and is also in the same group, and forwards the incoming call thereto.
In addition, Patent Document 2 proposes a method in which, in order to deal with situations where a forwarding destination is also incapable of communication, forwarding is performed to another mobile phone or fixed telephone in the same communication area among multiple registered incoming call forwarding destinations in the event that a mobile phone or a fixed telephone is incapable of receiving the incoming call and a pre-registered forwarding destination is also incapable of receiving the incoming call.
Patent Document 1: Japanese Patent Laid-Open No. H7-284154
Patent Document 2: Japanese Patent Laid-Open No. 2001-245357